A “humanoid robot” can be defined as a robot exhibiting certain attributes of the appearance and of the functionalities of a human being such as a torso, a head, arms, legs, the capacity to communicate orally with a human being using voice recognition and synthesis means, etc. The aim of this type of robot is to reduce the cognitive distances between man and machine. One of the most important features of a humanoid robot is its capacity to sustain a dialog that is as natural as possible with a human speaker. This capacity is essential for the development of “companion robots”, intended to assist the elderly, sick or simply people who are alone in the necessities of daily life, and to provide these people with an acceptable substitute to the presence of a human personal assistant.
The dialog methods for humanoid robots known from the prior art are not satisfactory because they lead to dialogs that are repetitive and stereotyped, and at the very least unnatural.
The paper by S. Rosenthal and M. Veloso “Mixed-Initiative Long-Term Interactions with an All-Day-Companion Robot”, in Dialogs with Robots: Papers from the AAAI Fall Symposium (FS-10-05), pages 97-102, describes a robot capable of guiding a human being in a visit, for example to the robotics department of a university. The robot is programmed to avoid the repetitions during the dialog; however, two different human speakers will be offered substantially identical dialogs.
The document U.S. Pat. No. 7,539,656 describes a method by which a machine dialogs with a human speaker to obtain information necessary to provide him or her with a service—for example, taking an order for breakfast. Such a dialog is very stereotyped and its purpose is not to reproduce a conversation. The method is therefore not suited to producing efficient “companion robots”.
The document U.S. Pat. No. 7,987,091 describes a method by which a machine holds a “personalized” and “progressive” dialog with one or more speakers. The dialog is personalized because the machine conducts the dialog based on a variety of information on the speakers, stored in its memory. It is progressive because the machine acquires new information in the course of the dialog. However, the dialog remains unnatural, because the phases of acquisition and of use of the information are clearly separate.